Large-size circulating fluidized bed boiler, air distributor and air distributor assembly

Abstract

The present invention provides a circulating fluidized bed boiler, comprising: furnace side walls; a ceiling; an air distribution plate provided at a bottom of a furnace; and at least one air distribution cone provided on the air distribution plate, wherein each air distribution cone extends upwards from the air distribution plate into an interior of the furnace and has a shape gradually tapered in an extending direction, cone side walls which form the air distribution cone are provided with secondary air ports, the cone side walls are separated from the furnace side walls, and a furnace combustion space is formed and surrounded by the ceiling, the furnace side walls, the air distribution plate, and the cone side walls. The present invention further relates to an air distributor for a circulating fluidized bed boiler, the air distributor being provided on an air distribution plate of the boiler, wherein the air distributor is in a form of an air distribution cone, which extends upwards from the air distribution plate into an interior of a furnace to form a shape gradually tapered in an extending direction, and secondary air ports are formed in air distribution cone side walls forming the air distribution cone. The present invention also relates to an air distributor assembly for a circulating fluidized bed boiler.

What is claimed is: 
     
       1. A circulating fluidized bed boiler, comprising:
 furnace side walls; 
 a ceiling; 
 an air distribution plate provided at a bottom of a furnace; and 
 at least one air distribution cone provided on the air distribution plate, 
 wherein: 
 each air distribution cone extends upwards from the air distribution plate into an interior of the furnace and has a shape gradually tapered in an extending direction, 
 enclosure side walls which form the air distribution cone are provided with secondary air ports, 
 the enclosure side walls are separated from the furnace side walls, and 
 a furnace combustion space is formed and surrounded by the ceiling, the furnace side walls, the air distribution plate, and the enclosure side walls, 
 wherein a space, which is not a part of the furnace combustion space and is in communication with an external environment of the furnace, is provided below the enclosure side walls, for arranging secondary air pipes therein. 
 
     
     
       2. The boiler according to  claim 1 , wherein:
 for each air distribution enclosure: 
 the air distribution enclosure comprises two first inclined enclosure side walls arranged to oppose to each other and two vertical enclosure side walls arranged to oppose to each other; 
 the two first inclined enclosure side walls are jointed or met at a top end of the air distribution enclosure and are connected with the two vertical enclosure side walls, and an arris line formed by the two jointed or met first inclined enclosure side walls is substantially parallel to the air distribution plate; and 
 the secondary air ports are provided in the two first inclined enclosure side walls respectively. 
 
     
     
       3. The boiler according to  claim 2 , wherein:
 the enclosure side walls are consisted of membrane walls; and 
 a first header is formed at the arris line so as to be parallel to the air distribution plate, the two first inclined enclosure side walls are collected into the first header, and a first membrane panel extends upwards and vertically from the first header. 
 
     
     
       4. The boiler according to  claim 3 , wherein:
 the two vertical enclosure side walls extend upwards and vertically to form second membrane panels. 
 
     
     
       5. The boiler according to  claim 2 , wherein:
 the enclosure side walls are consisted of membrane walls; and 
 the two first inclined enclosure side walls are collected into a tee pipe at the arris line and communicate with two branches of the tee pipe respectively, and a third branch of the tee pipe extends upwards and vertically to form a first membrane panel. 
 
     
     
       6. The boiler according to  claim 2 , wherein:
 the enclosure side walls are consisted of membrane walls; 
 the two first inclined enclosure side walls are jointed at the arris line, then extend upwards and vertically and are parallel with each other so as to form a first membrane panel, which is a double-layer panel. 
 
     
     
       7. The boiler according to  claim 4 , wherein:
 a T-shaped extended heating panel is formed by the first membrane panel and the second membrane panel at an end of the arris line formed by the two jointed or met first inclined enclosure side walls, wherein the first membrane panel composes the vertical of the T shape, while the second membrane panel composes a the horizontal of the T shape, and the first membrane panel and the second membrane panel are welded together by fins. 
 
     
     
       8. The boiler according to  claim 1 , wherein:
 for each air distribution enclosure: 
 the air distribution enclosure comprises two first inclined enclosure side walls arranged to oppose to each other and two second inclined enclosure side walls arranged to oppose to each other, 
 the two first inclined enclosure side walls are jointed or met at a top end of the air distribution enclosure and are connected with the two second inclined enclosure side walls, and an arris line formed by the two jointed or met first inclined enclosure side walls is substantially parallel to the air distribution plate; and 
 the secondary air ports are provided in the two first inclined enclosure side walls respectively. 
 
     
     
       9. The boiler according to  claim 8 , wherein:
 the enclosure side walls are consisted of membrane walls; and 
 the two first inclined enclosure side walls are collected into a tee pipe at the arris line and communicate with two branches of the tee pipe respectively, and a third branch of the tee pipe extends upwards and vertically to form a first membrane panel. 
 
     
     
       10. The boiler according to  claim 8 , wherein:
 the enclosure side walls are consisted of membrane walls; 
 the two first inclined enclosure side walls are jointed at the arris line, then extend upwards and vertically and are parallel with each other so as to form a first membrane panel, which is a double-layer panel. 
 
     
     
       11. The boiler according to  claim 9 , wherein:
 the two second inclined enclosure side walls are jointed with the first inclined enclosure side walls, then extend upwards and vertically and parallel with each other so as to form second membrane panels. 
 
     
     
       12. The boiler according to  claim 11 , wherein:
 a Y-shaped extended heating panel is formed by the first membrane panel and the second membrane panel at an end of the arris line formed by the two jointed or met first inclined enclosure side walls, wherein the first membrane panel composes the vertical of the Y shape, while the second membrane panel composes a V-shaped portion of the Y shape, and the first membrane panel and the second membrane panel are welded together by fins. 
 
     
     
       13. The boiler according to  claim 1 , wherein:
 the air distribution cone comprises a lower portion adjacent to the air distribution plate and an upper portion away from the air distribution plate, wherein the lower portion extends upwards and vertically from the air distribution plate, and the upper portion extends upwards to be tapered from a joint with the lower portion. 
 
     
     
       14. The boiler according to  claim 1 , wherein:
 a section of the air distribution cone parallel to the air distribution plate is formed into an oblong shape or a polygon shape having more than 4 sides. 
 
     
     
       15. The boiler according to  claim 1 , wherein:
 an arrangement of the air distribution enclosures is symmetrical with respect to a first furnace bisecting section perpendicular to front and rear walls of the furnace. 
 
     
     
       16. An air distributor for a circulating fluidized bed boiler, the air distributor being provided on an air distribution plate of the boiler, wherein:
 the air distributor is in a form of an air distribution enclosure, which extends upwards from the air distribution plate into an interior of a furnace to form a shape gradually tapered in an extending direction, and secondary air ports are formed in air distribution enclosure side walls forming the air distribution enclosure, 
 wherein a space, which is in communication with an external enviornment of the furnace, is provided below the enclosure side walls, for arranging secondary air pipes therein. 
 
     
     
       17. The air distributor according to  claim 16 , wherein:
 the air distribution cone comprises two inclined enclosure side walls, which are arranged to oppose to each other, and are jointed or met at a top end of the air distribution enclosure to form an arris line which is substantially parallel to the air distribution plate; and 
 secondary air ports are provided in the two inclined enclosure side walls respectively. 
 
     
     
       18. An air distributor assembly for a circulating fluidized bed boiler, comprising:
 the air distributor according to  claim 17 , wherein the enclosure side walls are consisted of membrane wall; and 
 a membrane panel extending upwards from the air distribution enclosure to form into an expanded heating surface, the membrane panel being in fluid communication with the membrane wall of a respective air distribution enclosure side wall.